Leave policy for edu-tech start up in Kerala - Is it okay to pay only the basic salary (currently set for 60% of CTC) for Casual Leave?

Hi, We are currently framing the leave policy for our newly formed Edtech start-up (15-20 employees) with a registered office in Kerala. The law proposes that 12 casual leaves, 12 sick leaves and 12 earned leaves (after one year) are to be allotted to employees. Following are my queries.
1. Is it okay to pay only the basic salary (currently set for 60% of CTC) for Casual Leave?
2. Is it okay to reduce the number of Casual Leave?

The leave salary should be on gross salary, the salary an employee should have earned had he worked on that day. If an employee absents from work, obviously, you will be deducting the leave without pay on the gross salary only and not on basic pay.

You can not reduce any leave, let it be CL, SL or PL.

In addition to the leaves admissible, your organisation has to declare 13 holidays with pay every year since your number of employees is 20. Out of these 4 holidays, January 26, May 1st, August 15th and October 2nd, are national holidays and are fixed for the respective days but 9 holidays should be for festivals falling on week days fixed in consultation with the employees in the organisation.